A bar chart displays national-level data from a CSV dataset, filtered to include all years for the "National" level. The visualization uses D3.js to create an SVG rendering, with a band scale for the x-axis and a linear scale for the y-axis. Bars are drawn as rectangles filled with steelblue, and axes are generated using `d3.axisBottom` and `d3.axisLeft`. The data is loaded asynchronously via `d3.csv` from a GitHub gist URL.